Mice are vocal creatures, using an extensive acoustic range that includes sounds both perceptible and entirely imperceptible to the human ear. Their communication system is complex, spanning the entire spectrum of audible noise and extending far into the ultrasonic domain. This means much of their social life remains undetectable to humans without specialized equipment. The sounds mice produce serve various functions, from warning of danger to facilitating social interactions.
Sounds Audible to Humans
The noises most people hear are typically the byproducts of a mouse’s movement and necessary maintenance behaviors. A common sound is the rapid, light scratching noise created by their claws gripping surfaces like drywall or wood as they move within walls or ceilings. This sound indicates activity, such as gathering nesting material or establishing a travel path inside a structure.
Another distinct, repetitive sound is gnawing or chewing, which is a dental necessity because their incisors grow continuously. Mice must chew on hard materials like wood, plastic, or wires to file their teeth down. This produces a high-pitched, chattering sound, often signaling a mouse seeking entry or processing nesting material. The light, quick pitter-patter of tiny feet scurrying across a floor signals their nocturnal search for food and water. When a mouse is trapped, injured, or cornered, it may emit a loud, high-pitched distress squeak, one of the few vocalizations clearly within the human audible range.
The Ultrasonic Communication System
Beyond the incidental noises of movement and chewing, mice possess a sophisticated communication method using sounds pitched far above human hearing. These are known as Ultrasonic Vocalizations (UVs), which are high-frequency calls spanning from 30 kHz up to 120 kHz. Since the upper limit of human hearing is around 20 kHz, UVs are acoustically invisible to us without specialized recording devices.
The biological advantage of using high-frequency sounds is that they attenuate, or lose energy, rapidly as they travel. This makes them less likely to be detected by predators with lower hearing ranges. UVs are thus an effective method for short-range, private communication between mice without alerting larger threats. These ultrasonic calls are complex, sometimes categorized as different “syllables” involving frequency modulations, providing a rich acoustic repertoire for social signaling.
Vocalizations and Social Behavior
Mice utilize their vocalizations to navigate a variety of social and environmental situations, using different calls for distinct purposes. The most studied use of UVs is in courtship, where male mice produce complex, melodic “songs” when encountering a female in estrus. These vocalizations are structured sequences of syllables believed to influence the female’s reproductive behavior.
Mouse pups use a different set of sounds when separated from their mother or littermates, emitting isolation calls frequently in the 40 kHz range. These calls function as distress signals, prompting the mother to retrieve the isolated pup to prevent exposure and cold. Adult mice also use UVs during same-sex social interactions, which can include territorial disputes or non-aggressive encounters.